fill column with last value from partition in postgresql

问题

I'm trying to return the last value of a partition and apply it to the rest of the column

For example, if I have the below...

ID    Date      Status
1     20150101
1     20150201
1     20150301
1     20150401  void
2     20150101
2     20150201
2     20150301 

I want to return this.

ID    Date      Status
1     20150101   void
1     20150201   void
1     20150301   void
1     20150401   void
2     20150101
2     20150201
2     20150301  

I've been playing around with the below and similar to no avail.

select 
ID, 
date, 
case when status is null then last_value(status ignore nulls) 
over (partition by id order by id, date) else status end as status
from table

Any help would be appreciated.

回答1:

You don't need the CASE statement:

SELECT id, date, last_value(status) OVER (PARTITION BY id ORDER BY date) AS stat
FROM table;

来源：https://stackoverflow.com/questions/28956967/fill-column-with-last-value-from-partition-in-postgresql